noun which may take the genitive case particle 'no', noun
congenital; hereditary; inborn
Medical term for conditions present from birth, whether genetic or not. Also used more broadly for innate traits.
彼は先天性の心臓病を持っている。
He has a congenital heart condition.
先天性の才能というものは確かに存在する。
Inborn talent certainly exists.
後天性 is the antonym, meaning 'acquired' (developed after birth).
From 先天 (せんてん, 'innate, before birth') + 性 (せい, 'nature, -ity').